Recently, it has been becoming essential to polish and planarize a surface of an insulating film by chemical mechanical polishing (CMP) in processes of manufacturing semiconductor devices such as LSIs. The reason of the planarization is to secure an exposure margin at the time of exposing a photoresist, and the like. In addition, when conductive plugs are formed in contact holes, CMP of a tungsten film is also carried out to leave the tungsten film only in the contact holes.
Meanwhile, diameters of semiconductor substrates have recently become larger, and wafers of 300 mm diameter have begun to be used in place of the conventional wafers of 200 nm diameter in the manufacturing processes of mass production of the semiconductor devices.
After the CMP, cleaning is carried out on a semiconductor substrate in order to rinse slurry and the like. However, when a conventional cleaning method for wafers with the diameter of 200 mm is used for the large diameter semiconductor substrate, there is a problem that foreign materials remain on the substrate after the cleaning.